It is necessary for a patient, who suffers from urinary disfunction to discharge urine out of the body through a urethra catheter left in the urinary bladder. To this end, several kinds of urination apparatus have been utilized. Most conventional urination apparatuses introduce urine into the urine-collecting bag through the urethra catheter inserted through the ureter into the urinary bladder and an on-off valve connected to an end of the urethra catheter. In such a urination apparatus, since urine always flows out of the body through the catheter left in the urinary bladder, the bladder does not expand and contract to effect normal urine-storage and urination and remains in an atrophied state. Consequently, the urinary bladder may completely lose its function after a long period of time.
Thus, several automatic urination apparatuses which actuate an on-off valve in response to detection of urine pressure in the urinary bladder have been proposed to maintain the function of the urinary bladder. However, these apparatuses have several problems in that they are large in scale, expensive, and inconvenient for a patient.